The fast deployment of various electronic devices, for example smart phones, internet of things (IoT) devices and sensors, has resulted in the continuous collection and monitoring of various types of information. The capability of collecting, monitoring, analyzing and consuming such streaming information has been a key driving force for different services. For example, for smart TV manufacturers, it has been beneficial to continuously share aggregated user data (in different forms of data summaries) with business partners and third-party service providers in order to provide adds-on services and increase revenue. As another example, it has been a common practice for sensors to continuously collect users' data in order to better personalized services.